The two transmission systems (NI and RoI) are connected via a double circuit 275kV line running from Tandragee in NI to Louth in RoI. Capacity reliance on the 275/220 kV cross-border circuit is restricted to 100MW North to South and 200MW South to North.
There are also two 110kV standby North-South interconnectors each with a capacity of 120MW:
- Strabane, Co Tyrone to Letterkenny, Co Donegal
- Enniskillen, Co Fermanagh to Corraclassy, Co Cavan
These facilities are primarily for use to allow the two grid companies to provide mutual technical assistance.
Proposed 400 kilovolt electricity interconnector
Interconnection is critical to long term security of supply and the release of operational efficiencies in the Single Electricity Market. Northern Ireland Electricity Networks (NIE Networks) and Eirgrid have proposed the construction of a new 400 Kilovolt overhead interconnector which will run from Turleenan, County Tyrone to Kingscourt, County Cavan.
For further information on the project, visit the System Operator for Northern Ireland (SONI) website.